Between-leg differences in challenging single-limb balance performance one year following anterior cruciate ligament reconstruction

Use of electromyographic biofeedback in rehabilitation following anterior cruciate ligament reconstruction: a systematic review and meta-analysis

BACKGROUND

Rehabilitation following anterior cruciate ligament (ACL) reconstruction surgery is essential to regain functionality and return to previous activity level. Electromyographic biofeedback may be an effective intervention for rehabilitation of patients following ACL surgery.

OBJECTIVE

To synthesize the available evidence on the effect of electromyographic biofeedback in the treatment of quadriceps strength following ACL surgery.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

PubMed, EMBASE, CENTRAL and Epistemonikos were searched.

ELIGIBILITY CRITERIA

Randomized clinical trials with patients undergoing ACL reconstruction surgery comparing biofeedback with a standard rehabilitation control group.

DATA EXTRACTION AND DATA SYNTHESIS

Two authors selected articles and performed data extraction. The analysed outcomes were strength, function, pain, knee extension and balance. The risk of bias of individual studies was assessed using the Cochrane Risk of Bias Tool. Results were combined through random-effects meta-analysis, reporting mean differences.

RESULTS

Eight articles were included in the qualitative analysis, and four articles were included in the quantitative analysis. The interventions lasted between 4 and 12 weeks. Three studies evaluated the effect of biofeedback on quadriceps strength; of these, two studies showed a significant difference in favour of the biofeedback group. In addition, biofeedback was found to improve knee extension [standardized mean difference - 1.3, 95% confidence interval (CI) - 1.74 to -0.86] and balance (one study). There was no significant difference in Lysholm score (mean difference -6.21, 95% CI -17.51 to 5.08; I2 =59%) or pain between the biofeedback group and the control group.

CONCLUSION

Electromyographic biofeedback in knee rehabilitation could be useful following ACL reconstruction surgery.

KEY MESSAGES

SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO (CRD42020193768).

A study regarding the anterior cruciate ligament remnant: Differences in balance and postural control between remnant-preserving and remnant-non-preserving patients

INTRODUCTION

The anterior cruciate ligament (ACL) is the most frequently injured ligament of the knee. However, quantitative studies on evaluate the postural control influence resulted from the ACL remnant preservation or not are scarce. The aim of this study is to evaluate the postural control of patients submitted to ACL reconstruction with and without preservation of the injured remnant in pre and postoperative periods.

METHODS

Eighteen patients underwent ACL reconstruction and separated into 2 groups according to the preservation or not of the remnant: (I) submitted to ACL reconstruction with preservation of the remnant (10 patients); (II) submitted to ACL reconstruction without preservation of the remnant (8 patients). They were assessed using the Lysholm score and force plate, which evaluated the patient's postural stability for remnant and non-remnant preservation in ACL reconstruction surgery.

RESULTS

Group I showed statistically significant subjective and objective improvements, both at 3 and 6 months. Additionally, improvement of the Lysholm test at 6 months in Group II was also statistically significant. Furthermore, the results of the Friedman test for the VCOP and VY variables of Group I, with support of the injured side in the force plate, showed a statistically significant difference both for pre and postoperative period at 3 months, compared to the 6-month postoperative period. The variables EAC and VX were statistically different for Group II, considering the preoperative period, 3 and 6 months postoperatively.

CONCLUSION

Preserving the ACL remnant in patients with ACL injuries has a positive impact on postural stability during recovery.

Low-frequency electrical stimulation alleviates immobilization-evoked disuse muscle atrophy by repressing autophagy in skeletal muscle of rabbits

BACKGROUND

The study aimed to investigate the effect of low-frequency electrical stimulation (LFES) on disuse muscle atrophy and its mechanism in a rabbit model of knee extension contracture.

METHODS

This study involved two experiments. In the time-point experiment, 24 rabbits were randomly divided into 4 groups: Control 1 (Ctrl1 group), immobilization for 2 weeks (I-2 group), immobilization for 4 weeks (I-4 group), and immobilization for 6 weeks (I-6 group). In the intervention experiment, 24 rabbits were randomly divided into 4 groups: Control 2 (Ctrl2 group), electrical stimulation (ESG group), natural recovery (NRG group), and electrical stimulation treatment (ESTG group). All intervention effects were assessed by evaluating the knee joint range of motion (ROM), cross-sectional area (CSA) of the rectus femoris muscle, and expression of autophagy-related proteins.

RESULTS

The time-point experiment showed that immobilization reduced the knee ROM, reduced the rectus femoris muscle CSA, and activated autophagy in skeletal muscle. The levels of five autophagy-related proteins [mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), autophagy-related protein 7 (Atg7), p62, and microtubule-associated protein light chain 3B-II (LC3B-II)] were significantly elevated in the skeletal muscle of the I-4 group. The intervention experiment further showed that LFES significantly improved the immobilization-induced reductions in ROM and CSA. Additionally, LFES resulted in a significant decrease in the protein expression of mTOR, p-mTOR, Atg7, p62, and LC3B-II in the rectus femoris muscle.

CONCLUSIONS

LFES alleviates immobilization-evoked disuse muscle atrophy possibly by inhibiting autophagy in the skeletal muscle of rabbits.

Medium-Term (Least 5 Years) Comparative Outcomes in Anterior Cruciate Ligament Reconstruction Using 4SHG, Allograft, and LARS Ligament

OBJECTIVE

To compare the clinical efficacy of anterior cruciate ligament (ACL) reconstruction with 4-strand hamstring tendon autograft (4SHG), allograft and the Ligament Advanced Reinforcement System (LARS) ligament, and to find the causes of cumulative failure or nonreturn to sport.

DESIGN

Retrospective case series.

SETTING

Department of Orthopedic Surgery, the second affiliated hospital of Soochow University, Suzhou, Jiangsu, China.

PATIENTS

Three hundred six patients with isolated ACL deficiency were included. Two hundred twenty-nine patients met the inclusion/exclusion criteria, and finally, 185 of these patients participated in this study.

INTERVENTIONS

Anterior cruciate ligament reconstruction using 4SHG, allograft, and LARS.

MAIN OUTCOME MEASURES

Objective knee function, subjective knee function, and information regarding return to sport, cumulative failure, and complications. Secondary: distribution of tunnel position and tunnel enlargement.

RESULTS

There were no statistically significant differences between the 3 groups regarding all the clinical objective and subjective results, return to sport, complications, or cumulative failures (P > 0.05). One hundred twenty-eight patients (69.2%, 128/185) returned to sport. Preoperative (after injury) Tegner scores were inferior to postoperative Tegner scores, and postoperative Tegner scores were inferior to preinjury Tegner scores (P < 0.01). The femoral tunnel malposition was significantly associated with cumulative failure (P < 0.05).

CONCLUSIONS

There were no statistically significant differences among the 4SHG, allograft, and LARS ligament in terms of the clinical outcomes after ACL reconstruction (ACLR) at 5-years follow-up. Interestingly, ACLR could improve the functional and motorial level of the knee, but patients had great difficulty in regaining the level of preinjury movement. In addition, the malposition of the femoral tunnel was an important cause of cumulative failure.

Alterations in medial-lateral postural control after anterior cruciate ligament reconstruction during stair use

BACKGROUND

Dynamic postural control during everyday tasks is poorly understood in people following anterior cruciate ligament reconstruction (ACLR). Understanding dynamic postural control can provide insight into potentially modifiable impairments in people following ACLR who are at increased risk for second ACL injury and/or knee osteoarthritis.

RESEARCH QUESTION

Determine whether measures indicative of dynamic postural control differ between individuals with and without ACLR during stair ascent and descent.

METHODS

Seventeen individuals with ACLR (>1 yr post-surgery) and 16 age and sex-matched healthy controls participated. Centre of pressure (COP) measures included: i) COP excursion, ii) COP velocity, and iii) dynamic time-toboundary (TTB). Mixed linear models were used to compare COP measures for the ACLR leg, non-ACLR leg, and healthy controls during stair ascent and stair descent.

RESULTS

There were no statistically significant differences observed during stair ascent (all p > 0.05). Several statistical differences were found during stair descent for individual with ACLR, but not between those with ACLR and healthy controls. The ACLR leg had higher medial-lateral COP excursion (mean difference 1.06 cm, [95 %CI 0.08-2.06 cm], p = 0.036; effect size = 0.38) compared to the non-ACLR leg during stair descent. In addition, the ACLR leg had a lower medial-lateral TTB (mean difference -13 ms [95 %CI -38 to 2 ms], p = 0.005; effect size = 0.49) and medial-lateral TTB normalized to stance time (mean difference -5.8 % [95 %CI -10.3 to 1.3 %], p = 0.012; effect size = 0.80) compared to the non-ACLR leg during stair descent. No statistical differences were observed for anterior-posterior measures during stair descent (all p > 0.05).

SIGNIFICANCE

Taken together, findings indicate that there are small to large differences in medial-lateral postural control in the ACLR leg compared to the non-ACLR leg during stair descent. Further work is required to understand clinical implication of these novel observations.

When Is It Safe to Return to Sport After ACL Reconstruction? Reviewing the Criteria

CONTEXT

There is an ever-increasing trend toward sports, fitness, and recreation activities, so the incidence of anterior cruciate ligament sports injuries has increased. Perhaps the greatest challenge for sports clinicians is to return the injured athlete back to his/her original sport at an even greater level of functional ability than preinjury. For this, rigorous and well-researched criteria are needed.

EVIDENCE ACQUISITION

Using medical subject headings and free-text words, an electronic search was conducted up to October 2018. Subject-specific search was based on the terms return to play and return to sport in combination with guidelines, criteria, and anterior cruciate ligament reconstruction.

STUDY DESIGN

Descriptive review.

LEVEL OF EVIDENCE

Level 2.

RESULTS

Five principal criteria were found, including psychological factors, performance/functional tests, strength tests, time, and modifiable and nonmodifiable risk factors.

CONCLUSION

The psychological readiness of the player is a major factor in successful safe return to sport (SRTS) decision making. Although strength, performance, and functional tests presently form the mainstay of SRTS criteria, there exists very little scientific evidence for their validity. More protection should be provided to athletes with known risk factors. Movement quality is important, if not more important than the quantifiable measures. As a result of the significantly high rerupture rate in young individuals, delayed SRTS should be considered preferably beyond 9 months postsurgery.

Hypoesthesia after anterior cruciate ligament reconstruction: The relationship between proprioception and vibration perception deficits in individuals greater than one year post-surgery

BACKGROUND

While surgical reconstruction restores mechanical stability following anterior cruciate ligament (ACL) rupture, many experience early-onset osteoarthritis despite surgery. Neurophysiological changes are hypothesized to contribute to knee osteoarthritis progression. Proprioceptive deficits have been reported following ACL injury/reconstruction; however, vibration perception threshold (VPT) has been less studied. This study explored relationships between pain, VPT, proprioception, function, and strength following ACL-reconstruction.

METHODS

Twenty individuals (27 ± 6 years; 10 males) (standard deviation) status-post ACL-reconstruction were compared with a control group. Measurements included VPT, proprioception (threshold to detect passive movement), pain, function (Knee Outcome Survey (KOS)) and isometric quadriceps strength. Group differences were assessed using Mann-Whitney U tests, side-to-side differences with Wilcoxon Signed Rank tests, and associations evaluated using Spearman correlations.

RESULTS

The ACL-reconstruction group had minor functional deficits (15 ± 11%) and resting pain (1.8 ± 1.7). Impaired VPT and proprioception (hypoesthesia) were demonstrated on surgical compared to contralateral and control limbs (p ≤ 0.008). Proprioception was significantly different between contralateral and control knees, but not VPT. Surgical knee proprioceptive deficits and VPT deficits were positively correlated (ρ = 0.462, p = 0.047) but not in controls (ρ = -0.042, p = 0.862). Strength was negatively correlated to pain (ρ = -0.589; p = 0.006), but not to KOS scores, proprioception or VPT (p ≥ 0.099).

CONCLUSION

Proprioceptive deficits following ACL injury have been ascribed to loss of afferent input from the torn ligament. Alternatively, multi-modality as well as contralateral sensory deficits suggest a spinal/supraspinal source of neurophysiological findings which may predispose to early osteoarthritis.

LEVEL OF EVIDENCE

III.

SeeSway - A free web-based system for analysing and exploring standing balance data

BACKGROUND AND OBJECTIVES

Computerised posturography can be used to assess standing balance, and can predict poor functional outcomes in many clinical populations. A key limitation is the disparate signal filtering and analysis techniques, with many methods requiring custom computer programs. This paper discusses the creation of a freely available web-based software program, SeeSway (www.rehabtools.org/seesway), which was designed to provide powerful tools for pre-processing, analysing and visualising standing balance data in an easy to use and platform independent website.

METHODS

SeeSway links an interactive web platform with file upload capability to software systems including LabVIEW, Matlab, Python and R to perform the data filtering, analysis and visualisation of standing balance data. Input data can consist of any signal that comprises an anterior-posterior and medial-lateral coordinate trace such as center of pressure or mass displacement. This allows it to be used with systems including criterion reference commercial force platforms and three dimensional motion analysis, smartphones, accelerometers and low-cost technology such as Nintendo Wii Balance Board and Microsoft Kinect. Filtering options include Butterworth, weighted and unweighted moving average, and discrete wavelet transforms. Analysis methods include standard techniques such as path length, amplitude, and root mean square in addition to less common but potentially promising methods such as sample entropy, detrended fluctuation analysis and multiresolution wavelet analysis. These data are visualised using scalograms, which chart the change in frequency content over time, scatterplots and standard line charts. This provides the user with a detailed understanding of their results, and how their different pre-processing and analysis method selections affect their findings.

RESULTS

An example of the data analysis techniques is provided in the paper, with graphical representation of how advanced analysis methods can better discriminate between someone with neurological impairment and a healthy control.

CONCLUSIONS

The goal of SeeSway is to provide a simple yet powerful educational and research tool to explore how standing balance is affected in aging and clinical populations.

The Relationship between Postural Stability and Lower-Limb Muscle Activity Using an Entropy-Based Similarity Index

The aim of this study is to see if the centre of pressure (COP) measurements on the postural stability can be used to represent the electromyography (EMG) measurement on the activity data of lower limb muscles. If so, the cost-effective COP data measurements can be used to indicate the level of postural stability and lower limb muscle activity. The Hilbert-Huang Transform method was used to analyse the data from the experimental designed to examine the correlation between lower-limb muscles and postural stability. We randomly selected 24 university students to participate in eight scenarios and simultaneously measured their COP and EMG signals during the experiments. The Empirical Mode Decomposition was used to identify the intrinsic-mode functions (IMF) that can distinguish between the COP and EMG at different states. Subsequently, similarity indices and synchronization analyses were used to calculate the correlation between the lower-limb muscle strength and the postural stability. The IMF5 of the COP signals and the IMF6 of the EMG signals were not significantly different and the average frequency was 0.8 Hz, with a range of 0-2 Hz. When the postural stability was poor, the COP and EMG had a high synchronization with index values within the range of 0.010-0.015. With good postural stability, the synchronization indices were between 0.006 and 0.080 and both exhibited low synchronization. The COP signals and the low frequency EMG signals were highly correlated. In conclusion, we demonstrated that the COP may provide enough information on postural stability without the EMG data.

Measurement of lower limb segmental excursion using inertial sensors during single limb stance

Advances in wearable technology have afforded health scientists and clinicians the ability to quantify clinically meaningful kinematic data with performance-based outcome measures in a variety of environments. However, no method for assessing segmental excursion of the lower limb during single limb stance (SLS) with wearable technology has been described in the literature nor has its clinical meaning been explored. This study introduces a clinically friendly measure to quantify lower limb segmental excursion during SLS with inertial measurement units (IMUs) which called the region of limb stability (ROLS). The purpose of this study was to determine the concurrent validity of an IMU-based system versus an optical motion capture system and to determine the effects of knee injury on the ROLS value. Excursion areas of five healthy adults were calculated with the IMU-based system and data were compared with an optical motion capture system. There were high correlations (0.82-0.93) and no significant difference (p > 0.05) in the tested parameters between the optical- and IMU-based systems. The IMU-based method was also implemented in five Division I athletes with knee injuries to determine changes in ROLS due to the injury. The ROLS Symmetry Index value offered a higher sensitivity and specificity to assess the presence of knee impairment than the sacral IMU. Quantified lower limb segmental excursion via IMUs can make better and more precise return-to-sport decisions that would decrease the risk of re-injury.

Electromyographic analysis of balance exercises in single-leg stance using different instability modalities of the forefoot and rearfoot

PURPOSE

To investigate the activity of lower extremity muscles in response to single-leg stance on a training device, destabilizing the forefoot while the rearfoot stands on a fixed plate and vice versa compared with a balance pad and the floor.

DESIGN

Cross-sectional study.

SETTING

University's laboratory.

PARTICIPANTS

Twenty-seven healthy adults.

METHODS

Surface electromyography and 2D video analysis were used to record the activity of lower extremity muscles and to control sagittal knee joint angle during single-leg stance trials under one stable control condition and five unstable conditions.

RESULTS

The majority of lower extremity muscles were significantly more active when the forefoot was destabilized while the rearfoot remained stable compared with the stable condition and the conditions where the forefoot was stable and the rearfoot unstable (p <0 .001). Mean change of knee joint angle was significantly increased under the conditions rearfoot stable/forefoot unstable (p = 0.001). The soleus muscle activation was significantly increased when balancing on the balance pad (p < 0.001).

CONCLUSIONS

Increased activity in the majority of lower extremity muscles and sagittal knee joint angles indicate that destabilizing the forefoot while the rearfoot remains stable is the most challenging balance task. Soleus muscle activation increased when performing ankle plantarflexion on the soft balance pad.

Men with unilateral Achilles tendinopathy have impaired balance on the symptomatic side

OBJECTIVES

To investigate single leg standing balance in males with mid-portion Achilles tendinopathy (AT).

DESIGN

Cross sectional case study.

METHODS

Centre of pressure (COP) path length was measured using a Wii Balance Board (WBB) in 21 male participants (20-60 years) with unilateral mid-portion AT during single-limb standing on each limb with eyes open and closed. Ultrasound imaging of both Achilles tendons was also performed by one blinded assessor, and the anteroposterior (AP) thickness and presence of pathology was determined. Comparisons were made between symptomatic and asymptomatic sides for key outcomes, and correlation between COP path length and variables of interest were investigated.

RESULTS

Symptomatic Achilles tendons demonstrated significantly increased AP tendon thickness (p<0.001). Participants with AT demonstrated increased COP path length (sway amplitude) on their affected side during the eyes closed task (p=0.001). Increased tendon thickness was associated with increased sway amplitude during the eyes open task on both the affected (rho=0.44, p=0.045) and unaffected sides (rho=0.62, p=0.003).

CONCLUSIONS

In males with AT, single-leg standing balance with eyes closed is impaired on the symptomatic side. This indicates that neuromuscular deficits affecting functional ability may be present in people with AT during more challenging balance activities. It is unclear if this deficit precedes the onset of symptoms, or is a consequence of tendon pain. Work is now needed to understand the mechanisms that may explain standing balance deficits among people with AT.